Prepared by the
Washington Utilities and Transportation Commission Pipeline Safety Program
10 a.m., Thursday, March 2, 2001
INTERSTATE PIPELINE STATUS
In the aftermath of Wednesday’s earthquake, the Washington Utilities and Transportation Commission (WUTC), in coordination with the Federal Office of Pipeline Safety (OPS) Western Regional Office, is conducting field inspections of the interstate pipelines in sensitive areas and areas susceptible to land movement.
So far, few problems have been detected by pipeline pressure sensors.
WUTC engineers along with the state-based federal inspector began performing field inspections immediately after the quake and will continue field inspections through this week and into next week if necessary.
The six interstate pipeline companies, operating in the earthquake zone, are in direct contact with the federal Office of Pipeline Safety to keep them apprised of their efforts in conducting leak surveys and conducting inspections on sensitive areas.
Williams Pipeline Company (Williams) has reported that after completing aerial and foot surveys, it has found no land movement, gas leakage or problems with its interstate pipeline in areas affected by the earthquake. Williams has installed pipe-monitoring devices (strain gauges) in areas prone to unstable ground movement, such as landslides, to detect any further land movement that may cause damage.
The company’s compressor station in Snohomish County shut down automatically as a result of the quake vibrations. The station, which maintains pressure inside the pipe, is designed to shut down under such movement until the company can establish that the facility is safe to operate. The company brought the station back on line shortly after inspection. Williams did not shut down any of their pipelines and is continuing to supply natural gas to all their customers in the region. The WUTC inspectors are coordinating with OPS and Williams to continue patrolling of the pipeline right-of-way, compressor stations and conduct leak surveys.
Olympic Pipe Line shut down its interstate pipeline immediately after the earthquake to evaluate the pipeline’s condition. Olympic plans to resume pipeline operation at 6 p.m. Thursday, March 1. Olympic identified a potential crack in the pipeline on Harbor Island in King County. However, after testing that area and other areas for cracks and leaks, no problems were found anywhere along Olympic’s system. Olympic Pipeline, OPS and the WUTC will continue patrolling and monitoring the pipeline for the indefinite future. Olympic Pipeline has also installed strain gauges and have not determined any ground movement. WUTC inspectors will be accompanying Olympic Pipeline personnel to inspect right-of-ways, pump stations, break out tanks and other facilities to further assess the conditions.
INTRASTATE PIPELINE STATUS
The WUTC has been in contact with all six of the intrastate pipeline companies operating in the earthquake zone. The companies have responded to over a 1,000 leak and odor complaints.
With three exceptions, only minor leakage and no significant problems have been reported. Puget Sound Energy (PSE) found a leak in a two-inch pipe serving a mobile home park (63 customers) in Olympia and another a leak in a four-inch main in Seattle. Both leaks have been stopped and service restored. Some customers in the mobile home park still need to have their furnace relit. PSE found an exposed main on East Lake Sammamish Road. The main was cut and capped without any customers losing service.
WUTC engineers are continuing on-going leak surveys and on-site patrols on the system.